Detailed analytical modeling for electromagnetic performance in actively shielded superconducting machines

This study presents detailed analytical modeling for electromagnetic performance analysis of actively shielded superconducting machines with air-cored slotless armatures. An actively shielded superconducting machine is composed of a type of nonmagnetic material to prevent saturation of the magnetic flux path, as the field coil has a high magnetic field, and a shield coil is installed on the outside for magnetic shielding. This study presents an analytical modeling technique that considers not only the distribution of armature coils with distributed windings but also the shapes of the field and shield coils. Analytical solutions for each domain are derived using electromagnetic theory, partial differential equations, and boundary conditions. Based on the analytical solutions, electromagnetic performances are analyzed. The analysis results obtained from the proposed analytical method are verified by comparing them with those of finite element analysis.